Process and apparatus for producing refrigeration



J y 1930 R. w. DAVENPORT 1,769,114

PROCESS AND APPARATUS FOR PRODUCING REFRIGERATION Filed Aug. 3, 1926 I N V EN TOR. Ransom 14 Davenparf ATTORNEY.

Patented July 1, 1930 UNITED STATESPATENT OFFICE RANSOM W. DAVENPORT, OF DETROIT, MICHIGAN, ASSIGNOR TO CHICAGO PNEUMATIC TOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY PROCESS AND APPARATUS FOR PRODUCING REFRIGERATION Application filed August 3, 1926. Serial No. 126,783.

This invention relates to heat transformin or refrigerating systems and includes bot process and apparatus. It particularly concerns the producing of thermodynamic effects on and with working substances characterized by the combination with a volatile liquid and its vapor of a' gas substantially inert to and insoluble in the liquid and its vapor as disclosed and claimed in my co pending application Serial No. 603,998, filed November 29, 1922.

In using such a working substance the vapor and gasare removed from one'vessel or evaporating system and compressed into another vessel or condensing system. From the latter the liquid is fed, and the vapor-gas is expanded, back into the first named system, thus performing a closed-cycle process in a closed-circuit apparatus as disclosed in my copending application Serial No. 15,172, filed March 12, 1925. It is a necessary result that the gas removed from the evaporator system must be transported into the condenser system and there confined at a higher pressure ()bviously, it follows that the rise in partial airpressure in the condensing system will depend somewhat upon the volume or size of the evaporator as compared with the condenser. If the former is of large cubical content, and the latter of small content, a very great gas pressure will occur in the condensmg system. If the gas pressure thus produced in the condenser is relieved by venting a portion to atmosphere, the system will thereafter 0 erate with a less total gas content than beibre. In consequence upon stopping the pump and permitting-the pressure of the high and low-side to equalize, the shutdown pressure will be considerably below the running pressure on the hi h side.

If now the proportions o the volumes of the evaporating and condensing systems as outlined above are reversed so that the volume of the hi h or condenser .side is very great as compared with the volume of the low or evaporator side, the-starting of the pump with both sides at atmospheric pressure wi I produce only a slight rise in the high or condenser side ressure. If the running pressures are su cient to get the desired low temperature on the low or evaporator side, no gas need be added to the system and the shutown pressures will be equal to atmosphere.

One object of the invention is to provide improved ways and means for condensing the vapor and for controlling the gas pressure in eat transforming systems of the described type. Another object is to devise ways and means by which the rise in total pressure in the condensing system may be kept moderate without unduly-increasing the sizeor volume (and consequently the bulk and cost) of the condensing system. Another object is to reduce the pressure differential of the high or condenser side and to keep the shut-down pressure close to a pre-determined figure. Other objects will be apparent from the detailed description which follows:

The invention consists essentiall in modifying previously disclosed processes by the utilization of an additional step which involves storing the gas. This step is preferably performed when the gas is at the lowest temperature existing on the high side and when it has been raised to its greatest partial pressure, which occurs after the partial vapor pressure has been lowered as a result of the condensing step. Suitable apparatus for the purpose may comprise a separate gas receiver connected into the high side beyond the condenser. This arrangement permits the use of smaller, cheaper and more compact apparatus.

The single diagrammatic view of my improved system shown in the accompanying drawing clearly discloses the inventlon.

In the drawing evaporator or boiler 1 containingthe liquid working substance is in dicated as disposed in a suitable chamber or cabinet A from which heat is to be extracted. Evaporator 1 is connected to the inlet of pump or compressor 2 driven by any form of prime mover (not shown) and the pump discharges into a condenser 3. The products of condenser 3 are fed back into evaporator 1 through a suitable control device 4:, thus forming a closed cycle system. The elements 1, 2 and 3 maybe of any known or suitable ype. I The system is placed 'in operation by disposing a body of some harmless, high-boiling volatile liquid, such as methylene chloride in the evaporator, and by filling the remainder of the system with a gas which is substantially inert to or insoluble in the liquid, such as, air, so that the shut-down pressure of the system is atmospheric. On starting pump 2, the gas and vapor in the upper part of evaporator 1 are drawn away causing the'liquid methylene chloride to vaporize and absorb heat. The vaporas stream is discharged by pump 2 at a higher temperature and pressure into condenser 3 where heat is removed so that the vapor is at least partly condensed. The liquid and gaseous products of condenser 3 are fed in predetermined quantity through device 4 which is capable of passing these products in contiguity as a single stream. This device, which may be properly termed an expander, may take the form of a Venturi nozzle with a fixed opening or of a float device such as disclosed in the copending application of myself and Mr. Harry S. Estler, Serial No. 114,900, filed June 10th, 1926. As so far described, both the process and apparatus are substantially the same as disclosed in my aforesaid coopending application, Serial No. 15,172, filed March 12, 1925.

The present invention consists in adding to the high side of thesystem, a receiver 5 of suitable size having a single connection 6 into the system intermediate condenser 3 and feeding device 4. This receiver stores the vapor gas after the condensing operation and is of such size as to make the content of the high side part of the system exceed the content of the low side to such an extent that when the system is in operation the high side running pressure is only slightly greater than. the shut-down pressure. Thus the process previously described is modified by performin the additional step which involves storlng the gas after its partial pressure has been raised by the lowering of the partial vapor pressure in the condenser proper. 1 By connecting receiver 5 into the system at the point shown, the vapor-gas mixture is stored at the lowest available temperature on the high side of the system and the additional process step may be described as filling the storage means with the vapor-gas'mixture previously cooled (by transversmg the condensed step) to approximately the temperature of the cooling medium.

In the operation of the modified system the gas from the low side, mixed with vapor, is compressed into the condensing system where the partial vapor pressure is lowered as the mixture is cooled and the liquid represented by this lowering of partial vapor pressure is condensed out, but the total pressure in the high side remains substantially constant, as set forth in my co nding application, Serial No. 15,172. At t e close of the condensing step the partial vapor pressure has been lowered and the artial air pressure has been raised. At this point the vapor-gas mixture passes into receiver 5 which then contains the gas compressed to a higher partial pressure than it had at the outlet of the compressor itself. Thus a suitable quantity of gas (dependent upon the size of receiver 5) removed from the low side is stored 0n.the high side until the apparatus shuts down and again equalizes the total pressure. With this arrangement the shut-down pressure for the high side may be kept about the same as the running pressure.

By preference, connection 6 leading to receiver 5 is so arranged that no liquid is allowed to find its way into receiver 5 so that the vapor stored therein tends toward the super-heated rather than the saturated state. Therefore, variations in the temperature of the receiver tend to aflect the pressure therein in the lesser degree defined by the laws of Boyle and Charles rather than in the greater degree corresponding with a liquid and its saturated vapor.

This invention distinguishes in certain respects from the process and appartus disclosed in my copending application, Serial No. 77,156, filed December 22, 1925, wherein a tank condenser is shown which serves the double purpose of a condenser and of an air receiver, the tank being utilized to retain a suitable volume of the vapor-gas mixture in a substantially static condition (while heat is removed from the exterior of the tank) to permit the vapor to condense out. With the present invention the condenser may be of any form, such as a tank, or some well known form of heat exchanger, as an automobile radiator, with which is now combined a se rate gas receiver connected to the system beyond the condenser.

While but one form of the invention has been herein shown and described, it is to be understood that the invention is not to be limited to the specific details thereof, but covers all changes, modifications and adaptations within the scope of the appended claims.

I claim as my invention:

1. In a closed cycle system utilizing as a working substance a volatile liquid and an inert gas, the thermodynamic process which comprises removin the gas and vapor from above a body of t e liquid to vaporize the same, raising the gas and vapor to a hi her temperature and pressure, removing eat from the vapor-gas mixture to condense the vapor, storing the residual. gas and vapor at said higher temperature and pressure, and feeding the condensate together with'a limited quantity of the gas and vapor in contiguitly into said body of liquid.

2. i n. a closed cycle s stem utilizing as a working substance a v0 atile liquid and an inert gas the thermodynamic process which comprises removin the gas and vapor from above a body of the liquid to vaporize the same, raising the gas and vapor to a hi her temperature and pressure, removing eat from the vapor-gas mixture to condense the vapor, storing the residual gas and vapor at said higher temperature and pressure and out of direct contact with the condensed liquid, and feeding the condensate together with a limited quantity of the gas and vapor in contiguity into said body of liquid.

*' 3. The thermodynamic process which comprises continuously circulating through a closed cycle system cggtaining a body of voltaile liquid a stream of vapor of the liquid and of inert gas, subjecting the stream to a lower pressure in the zone containing the body of liquid and causing the same to absorb heat and thereafter subjecting the stream to a single higher pressure and causing it to give up heat, and storing a part of the circulated vapor-gas stream at said higher pressure.

4. The thermodynamic process which comprises continuously circulating through a closed cycle system containing a body of voltaile liquid a stream of vapor of the liquid and of inert gas, subjecting the stream to a lower pressure in the zone containing the body of liquid and causing the same to absorb heat, and thereafter subjecting the stream to a single higher pressure and causing it to give up heat, and storing a part of the circulated vapor-gas stream at said higher pressure and at the point of highest partial pressure of the gas component.

5. The thermodynamic process which comprises continuously circulating through a closed cycle system containing a body of vola-.

tile liquid a stream of va or of the liquid and of inert gas, subjecting t e stream to a lower pressure in the zone containing the body of liquid and causing the same to absorb heat and thereafter subjecting the stream to a smgle higher pressure and causing it to give up heat, and storing a part of the circulated vapor-gas stream at said higher pressure and at the point of lowest temperature for said pressure.

6. The thermodynamic process which comprises continuously circulating through a closed cycle system-containing a bod of volatile 1i uid a stream ofvapor of e liquid and of inert gas, subjecting the stream to a lower pressure in the zone containing the body of H uid and causing the same to absorb heat and t ereafter subjectin the stream to a single higher ressure an causing it to give up heat, an increasing the volumetric capacity of the high side part of the system as compared with the low side part to predetermine the high side working pressure.

7. In the process of transforming heat inmixed gas and vapor while liquefying the vapor and raising the partial gas pressure,'the

step comprising the removing of a portion of said gas and vapor after the aforesaid operations thereon and storing said gas and vapor out of direct contact with the condensed iquid but at the same total pressure.

8. A mechanically operated refrigerating system of the closed cycle type having high and low pressure parts, and means main taining the operating high side pressure substantially the same as the equalized shut-down pressure of both sides.

9. A refrigerating s stem of the closed cycle type having a con enser, an evaporator, a pump for providing an unbalanced pressure in the system, a feeding device capable of passing in limited amount the substance acted upon by said pump from said condenser to said evaporator and to maintain the unbalanced pressure condition of the system so long as said pump is in operation, and means cooperating with said pump and said device for maintaining the pressure in a part of the system substantially constant regardless of whether said pump is in operation or not. 1

10. A refrigerating system of the closed cycle type having a condenser, an evaporator, a pump for providing an unbalanced pressure in the system, a feeding device capable of passing in limited amount the substances acted upon by said pump from said condenser to said evaporator and to maintain the unbalanced pressure condition of the system so long as said pump is in operation, and means comprising a storage receiver arranged to cooperate with said pump and said device for maintaining the pressure in a part of the system substantially constant regardless of whether said pumpis in operation or not.

11. In a heat transforming system, in combination, an evaporator, a pump and a condenser connected together to form a closed circuit, and means interposed between said condenser and said evaporator to increase the volumetric capacity of said system and to contain gaseous products only.

12. In a heat transforming system, in combination, an evaporator, a pump, and a condenser connected together to form a closed circuit, and a storage chamber connected to said circuit between said condenser and said evaporator and having a single connection for fluid.

13. In a heat transforming system, in combination, an evaporator, a pump and a condenser connected together to form a closed circuit, and means for storing the uncondensed products of said condenser out of contact with the condensate delivered by said condenser.

14. A heat transforming system utilizing as a working substance a volatile liquid and an inert gas, said system comprising an eva oravolving the removal of heat from a body OflltOr, a pump, a condenser and a feeding evice i said segregated portion being stored in a substantially dry condition and out of contactconnected together into a closed cycle system, said device being arranged to pass both the gaseous and the liquid products of said condenser in contiguity into said evaporator, and a storage receiver for the gaseous roducts of said condenser connected into sai system adjacent said device and maintained atthe samepressure as said condenser, said receiver beilng arranged to contain gaseous products on 1%. In a heat engine utilizing as a working substance a liquid and its Vapor combined with a gas, an evaporator containing a body of the liquid, a compressor, a condenser, and an expander, said parts bein connected together to form a closed cyc e system, and means for segregating and storing a portion of the circulated vapor-gas mixture on the high pressure side of the system at the lowest available temperature, at condenser pressure, and out of contact with any liquid.

16. In a heat engine utilizing as a working substance a liquid and its vapor combined with gas, an evaporator for containing a body of the liquid, a compressor, a condenser, and

an expander, said parts being connected to gether to form a closed cycle system, and means for segregating and storing a portion of the circulated vapor-gas mixture after being subjected to the condensing operation,

with the liquid. I

17. In a heat engine utilizing as a working substance a liquid and its vapor combined with a gas, an evaporator for containing a body of the li uid, a compressor, a condenser, and an expan er, said parts beingconnected together to form a closed cycle system, and a storage receiver connected into said system between said condenser and said expander for segregating and storing a sufiicient portion of the vapor-gas mixture out of direct contact with the condensed liquid to make the operating and the shut-down pressure of the high side of the system substantially the same, said receiver having a single connection servinas a gravity drain to said expander.

igne by me at Detroit, Wayne County, Michigan, this 31st day of July, 1926.

RANSOM W. DAVENPORT. 

